Module framing 

v1 broker wire framing — [u8 framing_version][u32 LE body_length][prost body].

Frozen-forever

This module implements THE truly-frozen-forever invariant of v1 per #228 “Frozen-forever commitments”: the framing byte is 1, the body length is a little-endian u32, and the body is a prost payload. Any future protocol version is signalled by changing the framing byte, which lets a v1 broker recognize a v2 client and return Refused{ERROR_VERSION_UNSUPPORTED} instead of decoding garbage.

Sizes

• MAX_FRAME_BYTES caps an arbitrary frame at 16 MiB. Larger frames cause the broker to disconnect.
• MAX_HELLO_BYTES caps the initial Hello envelope at 64 KiB. Larger Hello frames cause the broker to return Refused and close. Hello-specific reads should pass MAX_HELLO_BYTES to read_frame_with_cap.

Sync, not async

Phase 1 ships a synchronous std::io::{Read, Write} implementation because the client cargo feature does not pull in tokio. The broker server (Phase 4) runs under feature = "daemon" (which does include tokio) and can wrap a TcpStream/NamedPipeServer either through tokio::io::sync_bridge or by re-implementing the wire layout on AsyncRead/AsyncWrite. The wire format is the same; only the surface API differs.

Enums

FramingError

Errors produced by read_frame/write_frame.

Constants

ENVELOPE_VERSION

Framing byte for v1. Alias of crate::broker::FRAMING_VERSION_V1 to match the name used in the #228/#230 specs verbatim.

MAX_FRAME_BYTES

Default per-frame size cap (16 MiB). Alias of crate::broker::MAX_FRAME_SIZE_BYTES.

MAX_HELLO_BYTES

Hello-envelope size cap (64 KiB). Alias of crate::broker::MAX_HELLO_SIZE_BYTES.

Functions

read_frame

Read one v1 frame from reader with the default 16 MiB cap.

read_frame_with_cap

Read one v1 frame from reader, rejecting bodies larger than max_bytes.

write_frame

Write one v1 frame to writer.